One-way valves for controlling flow in fluid systems are relatively common. Valves having one condition permitting flow in one direction within a system while, in a second condition, remaining opened or closed are less common.
For example, U.S. Pat. No. 3,308,846 discloses a pressure relief valve which is closed by the combined forces of an energized solenoid and a spring element. When a predetermined system pressure is sensed the solenoid is de-energized. The system pressure force overcomes the spring element force so the valve opens to vent the system to the atmosphere and relieve the pressure. Sensing a reduced system pressure re-energizes the solenoid, reclosing the valve.
U.S. Pat. No. 5,056,556 discloses a solenoid and single spring associated with a complex, multipart valving arrangement. The '556 patent valve is described as functioning as a relief valve as well as an on-off valve.
U.S. Pat. No. 4,631,923 discloses a valve arrangement in which a valving member is acted upon by a compression spring to close the valve and alternatively, when the solenoid is energized, by a tension spring to enable flow.
The prior art proposals did not provide compact, easily manufactured valve assemblies of relatively few, simple parts and did not provide for consistently precise and effective valve operation.
The present invention provides a new and improved fluid flow control valve having one condition for enabling one-way system fluid flow and a second condition in which the valve is open or closed to system flow and wherein the valve is of simple, compact construction, easily manufactured from relatively few parts.